Orthopaedic Surgery/Distal Radius Fractures
|Distal Radius Fractures|
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A fracture of the distal radius is the most common fracture referred for orthopedic consultation from the emergency room. While classification systems abound and eponyms linger in common parlance, neither descriptive system really provides suitable common ground for communication as to the particulars of these fractures. Communication typically over the phone or otherwise without the films available for review should at least convey enough information to allow a preliminary decision as to what treatment is required be it a splint and follow-up for a cast within a week, or a prompt reduction either closed or with internal fixation.
Tenting of the skin due to severe deformity, or neurovascular compromise, or an open injury should all warrant prompt attention to at least achieve a provisional reduction and an initial formal irrigation of the fracture site in the case of an open injury if definitive treatment needs to be put off.
The degree of energy imparted to create the fracture may be gleaned in part by the fracture pattern and in part by the mechanism of injury. The likely stability of the fracture with simple closed reduction will be a function of the amount of energy imparted and the baseline strength of the bone, thus a fall in a 60 year old woman may be more likely to collapse after an initial reduction than will a fracture sustained in a fall from a height in a 20 year old. The fracture pattern may be the same in each and the degree of comminution may be the same. The better bone stock of the younger patient may improve the prospect for closed treatment, on the other hand the long term impact of slight residual step off and a stiffer wrist due to prolonged immobilizaton might tend to favor plating of such a fracture. Thus the decision making is complex and not especially amenable to a well defined protocol or algorithm. It is typical that a secondary procedure will be required in 15% of cases when initial closed management is pursued with the expectation of that being the definitive treatment. Fortunately there is little lost if an initial effort at closed reduction and then early follow-up with radiographs which will be telling of the inherent stability of the reduction. Indeed the feel of the reduction how readily it tends to slip back, how much of a mold or how awkward a wrist position is needed to maintain a reduction will predict its behavior and the patient may be counceled accordingly as to the likely need for secondary surgery once the swelling has subsided. If the fracture seems to require longitudinal traction to maintain reduction without a splint on, then the something close to the initial position in the original unreduced film is the likely outcome with closed treatment. It is not unusual to be surprised however when the follow-up film at one week looks anatomic but if the initial impression is unfavorable it is prudent to see the patient back at three weeks as a loss of reduction may yet occur readily in this time frame. Even beyond that point, late loss of reduction leading to malunion remains a risk with closed management. The occurrence of the nascent malunion treated at 6 weeks after an extended effort at closed management, is a salvagable situation but not ideal, as the patient is already pretty stiff, and their hopes of avoiding surgery are dashed and now surgery is added with a more difficult dissection effectively losing ground on the healing biology as it is necessary to take the fracture down to affect reduction.
Making the correct choice the first time then has its merits, and the ever improving technology for internal fixation of this fracture makes the surgical option more appealing still.
Through the late 80's until the mid 90's external fixation, then augmented external fixation with k wires of even a plate was the typical default treatment when closed management was not suitable. The initial hypothesis of ligamentotaxis alone maintaining a reduction with an external fixator alone proved problematic especially from the standpoint of finger stiffness. Augmented external fixation relies of the ligamentotaxis to achieve reduction but then the distraction is relaxed once k wires were placed retaining the fixator as a neutralization device, and positioning the wrist ideally in slight extension to facilitate rehabilitation of the fingers. Observing a lack of distraction at the midcarpal joint is a good indicator that there is no undue amount of distraction. The placement of k wires percutaneously is risky recognizing that it is indeed feasible to transfix a tendon or nerve with this technique. A nerve pierced may produce a dysfunction long after the fracture is expertly healed. Instead the skin is incised a hemostat is used to spread down to bone, a drill guide is used and the k wire is placed using it as a joy stick to refine the reduction if needed. If feasible leaving the pins cut off below the skin is more comfortable and lessens the risk of pin tract infection, but may require an anesthetic to remove the pins at 6 to 8 weeks. Generally if the pins can be removed at 4 weeks as for a relatively stable fracture, then leaving the pins out works fine. Beyond 4 weeks this approach seems more problematic. When the buried pins are to be removed they should be directly visualized again to avoid inadvertent injury to closely adjacent nerves which may be injured by blindly placed needle drivers seeking out the pin.
Augmented external fixation may yet be the best option in high energy fractures with lots of comminution. Adding a forearm neutral sugar tong splint may avoid difficulties with the distal radio-ulnar joint which can at times be unstable in pronation, especially when the weight of the fixator tends to direct the forearm into pronation. Elbow motion to full extension in such a splint is feasible by cutting a smile out of the back of the sugar tong splint.